NC State Extension

Pest Problems After Storms – Rodents

Mouse damage to box in storage

Mice will chew into boxes and use them for nesting or nesting material  (Photo: M. Waldvogel, NCSU)

Rain and wind can flood and damage rodents’ natural nesting spots which forces them to seek higher ground including inside your home (particularly into “high ground” such as attics). Damaged household goods, cut tree trunks and limbs, and other storm debris that are left piled on the property or become lodged in ditches or along streams quickly become homes for displaced rodents.  Loosened soil around holes left by fallen trees create ideal burrowing sites. Damage to your home’s exterior can provide animals with easier access to sheltered areas, such as your crawlspace, basement, attic or even wall voids. People involved in cleanup and repairs may carelessly discard food and beverage items, which quickly attract rodents searching for food.

  1. Watch for signs of rodent activity:
    • Norway rats (our most common rat species) usually nest in underground burrows (right). However, in flooded areas, they will move to higher ground and may even nest indoors. Roof rats typically nest above ground including in trees and mice will nest almost anywhere.
    • Mice and rats can chew through many materials including siding, sheetrock, cardboard boxes, etc., to gain entry to an area.
    • Rodent fecal droppings will often be found in indoor nesting or feeding areas.
  2. As soon as possible:
    • Clear debris that provide protective cover for rodents around houses and buildings. Debris that cannot be removed from the site immediately, should be placed as far as possible from the building.  That may be difficult or impossible particularly in neighborhoods.
    • When time and conditions allow, trim back lawns and overgrown vegetation near buildings to eliminate protective cover for rodents.
  3. Remove or contain potential food sources such as household trash, spoiled or discarded food, bird feed, or grass seed in a storeroom, etc., that might attract mice and rats.
  4. Do not leave bowls of pet food outdoors overnight. They attract rats and other animals that can pose other problems, such as raccoons, skunks, and opossums.
  5. Exposed ductwork in foundation where AC unit has been removed.

    Rodents can enter your crawlspace through openings where air conditioners or other utilities have been removed.

    Depending on their age and size, rats can fit through openings as small as a quarter and mice may fit through dime-sized openings. Seal gaps around water pipes, utility line entry points, vents, crawlspace accesses and doors. Rodents can chew easily through foam and dried caulk to gain entry. Use sheet metal or 1/4-inch mesh galvanized hardware cloth to close large openings.

  6. Snap traps and glue boards can be used to capture rats and mice indoors. Bait the trigger mechanism with a food item such as corn (or another grain), peanut butter or oatmeal.  Never place traps in areas where children and pets may be able to reach them. Check the traps daily and dispose of carcasses quickly and appropriately to avoid problems with flies. When handling traps that have caught rodents, wear gloves (preferably ones that are disposable or  can be rinsed in detergent or bleach). If you don’t want to reuse the trap, you can pick it up with an inverted plastic trash bag or grocery bag, seal the bag, and dispose of it properly.
  7. Rodent baits are usually effective for mouse and rat control; however, they must be used with great care.  Baits should only be used in tamper-resistant bait stations and never placed where children, pets or wildlife can get to them.  The disruptions that take place during and after a storm, as well as during subsequent clean-up activities, also disrupt normal rodent behavior and make them less likely to visit bait locations.  Do not use “place packs” or other types of rodent bait where they can easily be removed and/relocated by rodents because they may drop the bait where it may be found and accidentally eaten by children (who confuse it with candy) or by pets or wildlife. Carelessly discarded trash may also provide a ready food source that distracts the rodents from finding/eating bait.  It may also make it difficult to place and maintain bait stations. Poisoned rodents may also die out in the open where wildlife (or loose pets) may consume them.  Do not use baits indoors because the rodent may die under the house, inside a wall or in another inaccessible area that prevents you from removing the carcass (and subsequent odor). Always follow the instructions on product labels carefully.

Written By

Photo of Dr. Michael WaldvogelDr. Michael WaldvogelExtension Specialist (Household & Structural Entomology) (919) 515-8881 mike_waldvogel@ncsu.eduEntomology and Plant Pathology - NC State University
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